GRUMMAN AMERICAN
FOR TRAINING USE ONLY – SECTION 7
MODEL GA‐7/COUGAR
AIRPLANE & SYSTEMS DESCRIPTIONS
7‐18
Issued: April 10, 1978
LANDING GEAR EMERGENCY EXTENSION
The bypassing of hydraulic fluid is accomplished by use of the emergency gear extension valve, located in the nose
section. The emergency gear extension control handle is located beneath the instrument panel. Landing gear
emergency extension is accomplished by bypassing hydraulic fluid from the up side of the gear actuators, directly
to the power pack reservoir. This releases the up pressure on the actuators, allowing the gears to free fall. Down
springs aid in placing the gears in full down position. Piston locks mechanically engage to lock the gear down.
Should the emergency gear extension handle be inadvertently left OUT, the landing gear will not retract.
FUEL SYSTEM
The GA‐7/Cougar has an independent fuel system incorporated into each wing, permitting each engine to operate
from its own fuel supply. However, the two fuel systems are interconnected by a cross feed system, which permits
fuel from one tank to be drawn by the engine on the opposite side. The fuel systems consist of two wing tanks,
sump tanks, auxiliary fuel pumps (electric), engine driven fuel pumps, selector valves, primer solenoid valves, fuel
drains, fuel vents, and associated plumbing. See Figure 7‐10 for fuel system schematic.
FUEL TANKS
The fuel bay areas (tanks) are integral parts of the wing, located between the main and rear wing spars. Solid end
ribs are used to close off inboard and outboard ends of the bay. Total volume (both tanks) is 118 gallons with 114
gallons useable in all flight attitudes. Each fuel bay is equipped with a quick drain valve.
VENT SYSTEM
The fuel bays are vented overboard through vent lines extending to the bottom of the outer wing. Vent lines from
the sump tanks extend to each respective main tank to prevent the sump tanks from becoming air locked.
SUMP TANKS
A sump tank is provided in each wing, inboard of the engine. Each sump tank is equipped with a quick drain valve.
AUXILIARY FUEL PUMPS
An electric auxiliary fuel pump is located in each wing, immediately forward of the sump tanks. An integral bypass
and check valve permits fuel flow through the pump while the pump is inoperative, but prevents reverse flow of
fuel. The electric auxiliary pumps are used as a source of fuel pressure in the event of an engine driven pump
failure. The auxiliary pumps should be operating during takeoff and landing to provide backup for the engine
driven pumps. Two auxiliary fuel pump switches, one for each tank, are located on the fuel selector panel. The
switches have two positions, labeled ON and OFF.
FUEL SELECTOR VALVES
A three position fuel selector valve is located inboard of each engine. The control for each valve is located on the
aft center console. The positions labeled on the controls are: ON, CROSS FEED, and OFF. The OFF position cannot
be selected without first pushing the safety button next to the control.
